Light source unit and thermally-assisted magnetic head

Abstract

A light source unit for thermally-assisted magnetic head includes a substrate member having a first bonding surface; a light source assembly attached on the first bonding surface of the substrate member and having a second bonding surface; and a heater circuit assembly formed between the substrate member and the light source assembly, the heater circuit assembly having a heater formed on the substrate member and two leads connected at two ends of the heater, the lead being thicker than the heater, thereby a distance between the heater and the second bonding surface is farther than that between the lead and the second bonding surface. The light source unit can reduce mechanical stress and thermal conduction between a light source assembly and a substrate member, thereby improving the performance of the light source assembly and the heater.

What is claimed is: 
     
       1. A light source unit for thermally-assisted magnetic head, comprising:
 a substrate member having a first bonding surface, 
 a light source assembly attached on the first bonding surface of the substrate member and having a second bonding surface; and 
 a heater circuit assembly formed within the substrate member, the heater circuit assembly having a heater formed within the substrate member and a first lead and a second lead connected at two ends of the heater, 
 wherein the substrate member comprises a connection pad layer and an insulation layer including a first insulation layer and a second insulation layer, 
 wherein the first lead, the second lead and the heater each are directly disposed on a same upper flat surface of the second insulation layer and directly sandwiched between the first insulation layer and the second insulation layer, and the first lead and the second lead each are thicker than the heater, thereby a distance between the heater and the second bonding surface is greater than that between the first lead and the second bonding surface and that between the second lead and the second bonding surface. 
 
     
     
       2. The light source unit according to  claim 1 , wherein the first bonding surface of the substrate member has a bonding area that is bonded to the light source assembly, and the heater is buried under the light source assembly and located within the bonding area. 
     
     
       3. The light source unit according to  claim 1 , wherein multiple layers are formed on the substrate member, and the substrate member further comprises a base layer, a buffer layer and a first bonding layer with the first bonding surface provided. 
     
     
       4. The light source unit according to  claim 3 , wherein a second bonding layer is formed on the light source assembly to provide the second bonding surface, and the second bonding layer is thinner than the first bonding layer. 
     
     
       5. The light source unit according to  claim 1 , wherein the second insulation layer is thicker than the first insulation layer, and thermal conductivity of the second insulation layer is lower than that of the first insulation layer. 
     
     
       6. The light source unit according to  claim 5 , wherein the first insulation layer is made of SiN or AlN, and the second insulation layer is made of SiO 2 , SiN or Al 2 O 3 . 
     
     
       7. The light source unit according to  claim 1 , wherein the heater is made of tungsten or platinum. 
     
     
       8. A thermally-assisted magnetic head, comprising a slider body and a light source unit attached on a surface of the slider body, wherein the light source unit comprises:
 a substrate member having a first bonding surface, 
 a light source assembly attached on the first bonding surface of the substrate member and having a second bonding surface; and 
 a heater circuit assembly formed within the substrate member, the heater circuit assembly having a heater formed within the substrate member and a first lead and a second lead connected at two ends of the heater, 
 wherein the substrate member comprises a connection pad layer and an insulation layer including a first insulation layer and a second insulation layer, 
 wherein the first lead, the second lead and the heater each are directly disposed on a same upper flat surface of the second insulation layer and directly sandwiched between the first insulation layer and the second insulation layer, and the first lead and the second lead each are thicker than the heater, thereby a distance between the heater and the second bonding surface is greater than that between the first lead and the second bonding surface and that between the second lead and the second bonding surface.